The present invention relates to monitoring of electrical components and, in particular, it relates to an improved device and a corresponding method for warning of deterioration of a starter mechanism of a combustion engine.
Operation of a combustion engine ordinarily involves activating a starter mechanism. In general, a combustion engine refers to any engine operating by combustion or burning of fuel in the presence of a supply of oxidation. A combustion engine may be part of a vehicle, where a vehicle may be any mobile device powered by the combustion engine for carrying or transporting persons or objects of any kind, for example, an automobile, truck, farm vehicle such as a tractor or cotton combine, train, airplane, or boat. A combustion engine may also be part of a stand alone, generally immobile, device, such as an electrical generator, cement mixer, or heavy duty power machinery. A starter mechanism of a combustion engine typically features a multitude of electrical and mechanical elements, including the basic elements of a battery as an initial source of electrical power, a starter motor for mechanically meshing with and turning the crankshaft of the engine motor, the engine motor crankshaft, a coil for generating high voltage required for continuous operation of the engine, and a myriad of related electrical and mechanical circuitry and connections among the various elements of the starter mechanism and related elements of the engine. In principle, a starter mechanism of a combustion engine operates in relation to an electrically and mechanically varying load, where the load features a varying combination of electrical and mechanical loads.
It is known that a vehicle battery, for any vehicle as described above, such as that used to activate or energize a starter mechanism for starting the motor of a combustion engine, has a limited life-span and must eventually be replaced. Typically, battery replacement is only performed once the battery is no longer able to start the engine. This situation may arise when a vehicle operator is in a hurry to drive somewhere, during rain and/or cold weather, at holiday times when garages are usually closed, or when one is a long distance from help. Battery failure is therefore a common source of aggravation for many vehicle operators on a daily basis.
A number of methods have been proposed to identify when a battery may fail to sufficiently activate or energize a starter motor and thus fail to enable starting of the vehicle engine. One method is to measure the specific gravity of the electrolyte within a battery. This procedure is ordinarily done by a professional or trained auto mechanic, since hazardous chemicals are involved during such a measurement. Another method involves measuring the internal resistance of a battery by using one of various procedures. This method also requires technical/professional knowledge and/or workers. Yet another method involves continuous measurement and display of battery voltage during the entire life of the battery.
An example of a system based on measuring internal resistance of a battery is disclosed in U.S. Pat. No. 5,339,017 to Yang which describes a device for checking the charge state of a vehicle battery. This device checks battery charge by indirectly measuring internal resistance of the battery. This is done by measuring voltage of a capacitor charged by a vehicle battery. Measurement is performed at a pre-determined time. At higher capacitor voltage, internal resistance of the battery is lower. The device provides visual display of capacitor voltage, thereby indicating battery internal resistance, which in turn shows the state of charge of the battery. Measuring internal resistance of a battery typically results in high consumption of energy and heating of the battery, potentially causing sparks leading to an engine fire or other damage if done by an improperly trained person.
To overcome limitations associated with the above described methods, Yaffe et al., in U.S. Pat. No. 5,818,333, which is incorporated by reference for all purposes as if fully set forth herein, disclosed a device and method for warning when a vehicle battery is about to run out, but is still able to start a vehicle motor, thereby allowing a vehicle operator to continue driving the vehicle, and prepare for timely replacement of the battery. The disclosed device 10, shown as a block diagram in FIG. 1, includes (a) a voltage level tester 11 for measuring, either directly or indirectly, a voltage across battery terminals 8 and 9 at the end of a given engine starting time interval, (b) a timer 12 responsive to activation of a starter mechanism to time the given engine starting time interval, (c) a counter 15 for maintaining a cumulative or incremental count of occasions on which the battery voltage is below a given level, and (d) an alarm unit 16 for providing a warning signal when the cumulative or incremental count exceeds a pre-determined number of counts. In a preferred embodiment, the voltage level tester continuously measures the voltage across the battery, and the timer identifies activation of the starter mechanism by a corresponding sudden drop in voltage across the battery.
According to the method for operating device 10 disclosed by Yaffe et al., the warning signal, in the form of an audible alarm or visual signal, provided when the incremental count exceeds a given number, is generated following activation of the starter mechanism or motor. The main objective of this procedure, that of alerting a vehicle operator, following engine starting, of deterioration of a starter mechanism in general, and of near failing battery charge in particular, may not be achieved for one or a combination of the following realistically limiting reasons.
First, following engine starting, activation of a standard audible alarm used in such an application may be insufficiently loud to overcome normal background noise internal and/or external to the vehicle, continuing henceforth from engine starting, in order to be effectively heard by the vehicle operator. With respect to noise internal to the vehicle, this is especially the case if vehicle accessories such as a radio and/or a climate control mechanism are simultaneously activated with engine starting, a situation quite commonly occurring as a consequence of a vehicle operator failing to turn-off all accessories prior to the time of previous engine turn-off. Moreover, depending upon the immediate environment of the initially parked vehicle, such an audible alarm simply may not be able to compete with substantially higher decibel levels of noise external to the vehicle, especially in urban environments.
Second, following engine starting, activation of a deteriorating starter mechanism visual warning signal appearing, for example, somewhere along the operator side of the vehicle dashboard, may not be noticed among the standard multitude of visual signals also displayed along the operator side of the vehicle dashboard. Third, following engine starting, the audible alarm and/or visual signal may malfunction or even be entirely absent due to circuit failure. Thus, the device and method for warning a vehicle operator of starter mechanism, or battery, deterioration as disclosed by Yaffe et al. are expected to be effective under essentially ideal engine starting conditions, but, are notably limited under realistic vehicle starting and operating conditions.
To one of ordinary skill of the art, there is thus a need for, and it would be highly advantageous to have an improved device and corresponding improved method for warning a vehicle operator of deterioration of a starter mechanism in which a motor is powered by a battery to start a combustion engine, prior to failure of the starter mechanism to enable starting of the engine.